1. Field of the Invention
This invention relates to an automatic seatbelt system for use in a motor vehicle, and more particularly to an improvement in the automatic seatbelt system for automatically fastening occupant restraining webbings about an occupant in the vehicle.
2. Description of the Prior Art
A seatbelt system has been adapted to restrain and protect an occupant in the event of an emergency situation such as a collision. However, the inconvenience or unease in fastening a seatbelt webbing often prevents the occupant from fastening the webbing willingly. To overcome this problem, there has been proposed an automatic seatbelt system capable of automatically fastening an occupant fastening webbing about the occupant upon his entering the vehicle.
Among the automatic seatbelt systems of the type described, one in which the webbing extends from a vehicle door to substantially the central portion of the vehicle via a position close to an occupant's seat is inexpensive and reliably operable and, hence, highly evaluated. In this automatic seatbelt system, as shown in FIGS. 1 through 3, one end portion of an occupant restraining inner webbing 1 is wound into a retractor 2, which is secured to a tunnel portion 4 projecting from substantially the central portion of a vehicle body 3. This retractor 2 winds the inner webbing 1 by its biasing force, and incorporates therein an inertia lock mechanism, not shown, for abruptly stopping the unwinding of the inner webbing 1 in the event of a vehicular emergency situation. The other end portion of this inner webbing 1 is passed through an opening 5a of a ring joint 5, then turned back therearound and sewn onto the webbing itself. The intermediate portion of an occupant restraining outer webbing 6 is inserted through the opening 5a of the ring joint 5, made movable in the longitudinal direction of the webbing. One end of the outer webbing 6 is engaged with the lower rear end portion of a vehicle door 8 through an anchor plate 7, and the other end thereof is secured thereto with a tongue plate 9. This tongue plate 9 is engaged with a buckle device 20 solidly secured to the upper rear end of the vehicle door 8, whereby both ends of the outer webbing 6 are engaged with the door. This buckle device 10 is provided with a release knob 11, and, when the occupant presses this release knob 11, the tongue plate 9 can be released from the buckle device 10. The inner webbing 1 and outer webbing 6 are interposed between the vehicle body 3 and the vehicle door 8 as described above, so that the webbings 1 and 6 can be automatically fastened about an occupant 13 seated on a seat 12 in accordance with the opening or closing of the door 8.
However, in the automatic seatbelt system of the type described, the outer webbing 6 is divided into two portions including a shoulder restraining belt and a lap restraining belt, bordering each other at a ring joint 5. Since the ring joint 5 is movable along the outer webbing 6, namely the shoulder and lap belt, a tension generated in the outer webbing 6 due to the forward movement of the occupant in the event of a collision generates a phenomenon in which the lap restraining belt is passed through the ring joint 5 and moved to the shoulder restraining portion. Or, the ring joint 5 may be raised upward without moving along the outer webbing.
In view of the phenomenon as described above, there has been proposed an automatic seatbelt system as shown in FIG. 4 where a guide lever 14 is fixedly provided at the inner side of the occupant's seat, and the substantially intermediate portion of the inner webbing 1 is passed through a slot or opening defined by a guide loop portion 15a formed at a webbing guide portion 15 of the guide lever 14.
With the above-described arrangement, the aforesaid phenomenon can be obviated by preventing the inner webbing from being raised upward. However, the webbing guide portion 15 of the guide lever 14 is fixed to a main body 16 of the guide lever, thus presenting the disadvantages to be described hereunder. Namely, for example, if the inclination angle of the webbing guide portion 15 is such that the inner webbing 1 can be freely passed therethrough when the occupant 13 is not seated on the seat 12, then the inner webbing 1 comes into pressing contact with the upper end of the guide loop portion 15a of the webbing guide portion 15 when the occupant 13 is seated on the seat 12, with the result that a so-called offset portion occurs in the inner webbing 1, thus necessitating a larger force to open or close the door and also causing a partial wear, and the like in the inner webbing 1. On the other hand, if the inclination angle of the webbing guide portion 15 is in such that the inner webbing 1 can be freely passed therethrough when the occupant 13 is seated on the seat 12, then the inner webbing 1 comes into abutting contact with the lower end of the guide loop portion 15a when the occupant 13 is not seated on the seat 12, thus presenting the disadvantage that the so-called offset portion occurs in the inner webbing 1. The offset portion also occurs depending on the adjustment of a seat position, physical build of the occupant and so forth where the webbing guide portion is in a fixed placement.